A person's source of motivation changes as they make progress toward their objectives, according to a new study.

We've all been there: We set a goal and, for one reason or another, we can't seem to stick to it. Maybe you set a New Year's resolution to drop that nagging extra 10 lbs you've been carrying around and got discouraged by your lack of progress. Perhaps you tried saving up for a big vacation but couldn't help spending that extra dough on fancy restaurants (which will hurt your wallet and your health).

Whatever the reason you weren't able to cross the finish line, you're probably wondering what you can do to fix it.

In the study, researchers conducted five separate experiments. They found that in the early stages of pursuing a goal (like, say, losing 10 lbs), people were driven by "promotion motivation"—meaning they were excited about looking better in the future—and they'll do positive things to shed that weight. As people came closer to achieving their goals, however, they were more motivated to avoid a negative outcome (like putting the weight back on), which the study authors called a "prevention mindset."

"Generally speaking, people in North America are predominantly promotion-focused—so they're good at starting goals, but not as good at accomplishing them," says Olya Bullard, Ph.D., a lead author on the study and assistant professor at the University of Winnipeg.

So: How can you change your own behavior?

People would probably have better luck completing their objectives if they focus on what they need to avoid to be succesful, particularly in the later stages of pursuing a goal, the study suggests. Some dieters even bet cash that they'll be able to lose weight, banking (literally) that their natural aversion to financial loss will help motivate them to drop weight instead of money.